1. Field of the Invention
The present invention relates generally to protecting artistic content in digitized form, and more particularly to preventing reuse of rented digitized music on a flash memory device after the device has checked the music back in to a vending machine.
2. Description of the Related Art
The advantages of digitized video and music are numerous, but one significant drawback is that being digitized, the content is relatively easy to copy perfectly, without authorization of the copyright owner. Indeed, widespread copying by pirates costs content owners billions of dollars per year. Thus, the present invention as well as the above-referenced parent applications understand that it is desirable to limit the unauthorized copying of digital audio and video.
One particular application that requires content protection is that of rented music. It happens that music CDs can be rented in certain jurisdictions, and then returned for a refund of a deposit at the end of the rental term. Along these lines, flash memory devices have been proposed that a user can insert into a music rental kiosk or other content vending apparatus, pay a fee to xe2x80x9ccheck outxe2x80x9d a particular song or album, which is recorded onto the flash memory. The flash memory device is then removed from the kiosk and inserted into an authorized player that plays the music. When the user is finished with the music, the user again inserts the flash memory into a kiosk, which xe2x80x9cchecks inxe2x80x9d the music by erasing it from the flash memory and refunding part of the rental fee to the user, like returning a deposit.
In another application, music is distributed electronically with the intention that it will be played by a flash memory music player for an end user. It is desirable, however, that a single downloaded song not become the source of many copies. To restrict the number of copies that can be made, the present invention recognizes that the client application of the music system might xe2x80x9ccheck outxe2x80x9d the song to each player, but restrict the number of copies that can be checked out at any one time to, e.g., three. To check out the song to additional players, one of the checked out copies would first have to be checked back in.
In any case, the problem addressed by the present invention is that of unscrupulous users, having checked out a music track, recording the data on another computer, then checking the music back in to receive their refund (or enable the music to be checked out to another player). In the rental context, the unauthorized copy of the music could then be downloaded from the computer onto the flash memory and replayed without paying royalties to the content owner.
One way to prevent the reuse of an unauthorized copy of a piece of digitized music is to arrange a complex cryptographic protocol between the flash memory device and the check in/check out application at the kiosk. Unfortunately, such protocols require a considerable number of logic gates on the flash memory device, which, owing to the nature of flash memory, is expensive and undesirable. The present invention recognizes that the principles set forth in the first of the above-referenced patent applications can be used to prevent the reuse of pirated music from a rental kiosk.
A system is disclosed for renting digitized content. The system includes at least one content vending apparatus, preferably a computer kiosk, storing digitized content, and at least one memory device, preferably a flash memory device, that can be engaged with the content vending apparatus. A media ID is stored on the memory device, with the vending apparatus using at least the media ID to derive a content key. The vending apparatus encrypts content using at least the content key, and then records the encrypted content on the memory device. At least one player-recorder is subsequently engageable with the memory device for decrypting and playing the content.
In a preferred embodiment, a media key block is accessible to the vending apparatus at least when the memory device is engaged therewith. The vending apparatus uses the media key block to derive the content key, prior to recording the content onto the memory device. Preferably, each player-recorder includes plural computer-usable device keys selected from a set of device keys for decrypting the content.
As intended by the present invention, the memory device can be engaged with the vending apparatus after the content has been recorded to check in the content to the vending apparatus by causing the content to be erased from the memory device. As part of the check in, the media ID is altered, preferably by incrementing the media ID.
In another aspect, a computer includes a data storage device including a computer usable medium having computer usable code means for checking in digital content from a memory device having a media ID. The computer usable code means includes computer readable code means for erasing the content. Also, computer readable code means are provided for altering the media ID.
In yet another aspect, a method for renting digitized content includes using a media ID on a memory device to derive an encryption key. The method then uses the encryption key to encrypt the content, which is then recorded onto the memory device to check out the content. The content subsequently can be checked in by erasing the content from the memory device and altering the media ID. Rental payment can be accepted from a user as a condition of check out, and a refund can be made to the user as part of check in.
The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: